Correct option is B. $$1.33\ \mu C/m$$
Electric field due to infinite line charges at a distance d is given as:
$$E=\dfrac{\lambda}{2\pi\varepsilon_0d}$$
$$\lambda=2\pi\varepsilon_0dE$$
Here,
$$d = 3 cm = 0.03 m$$
$$E = 8 \times 10^4 N/C$$
$$\varepsilon_0 = \text{Permittivity of free space}$$
$$\dfrac{1}{4\pi\varepsilon_0}= 9 \times 10^9 N m^2 C^{−2}$$
$$\lambda=\dfrac{0.03\times8\times10^5}{2\times9\times10^9}$$
$$= 1.33 \mu C/m$$
Therefore, the linear charge density is $$1.33 \mu C/m$$.